TY - JOUR
T1 - Biochemical and immunological comparisons of carbohydrate-binding protein 35 and an IgE-binding protein.
AU - Laing, J. G.
AU - Robertson, M. W.
AU - Gritzmacher, C. A.
AU - Wang, J. L.
AU - Liu, Fu-Tong
PY - 1989/2/5
Y1 - 1989/2/5
N2 - The predicted amino acid sequence of carbohydrate-binding protein 35 (CBP35; Mr approximately 35,000), a galactose-specific lectin in many mouse and human cells, has been compared to the predicted sequence of an IgE-binding protein (epsilon BP) originally identified in rat basophilic leukemia cells. The sequences of the two proteins showed that: (a) 85% of the amino acid residues are identical; (b) the polypeptide chains are comprised of two distinct domains; and (c) highly conserved internal repetitive sequences are present. Consistent with these observations, antisera raised against CBP35 or against a synthetic peptide derived from the epsilon BP sequence cross-reacted with both proteins. Moreover, fractionation of extracts of mouse 3T3 fibroblasts over an IgE-Sepharose affinity column showed that CBP35 bound to IgE; this binding was reversed by addition of lactose. Conversely, fractionation of extracts of rat basophilic leukemia cells over an affinity column of Sepharose derivatized with N-(epsilon-amino-caproyl)-D-galactosamine showed that epsilon BP was a galactose-binding protein. Furthermore, epsilon BP bound to IgE-Sepharose could be eluted by lactose. Finally, transcription and translation in vitro of the cDNA corresponding to epsilon BP yielded a polypeptide containing carbohydrate-binding activity. All of these results strongly support the conclusion that CBP35 and epsilon BP are mouse and rat homologues, respectively.
AB - The predicted amino acid sequence of carbohydrate-binding protein 35 (CBP35; Mr approximately 35,000), a galactose-specific lectin in many mouse and human cells, has been compared to the predicted sequence of an IgE-binding protein (epsilon BP) originally identified in rat basophilic leukemia cells. The sequences of the two proteins showed that: (a) 85% of the amino acid residues are identical; (b) the polypeptide chains are comprised of two distinct domains; and (c) highly conserved internal repetitive sequences are present. Consistent with these observations, antisera raised against CBP35 or against a synthetic peptide derived from the epsilon BP sequence cross-reacted with both proteins. Moreover, fractionation of extracts of mouse 3T3 fibroblasts over an IgE-Sepharose affinity column showed that CBP35 bound to IgE; this binding was reversed by addition of lactose. Conversely, fractionation of extracts of rat basophilic leukemia cells over an affinity column of Sepharose derivatized with N-(epsilon-amino-caproyl)-D-galactosamine showed that epsilon BP was a galactose-binding protein. Furthermore, epsilon BP bound to IgE-Sepharose could be eluted by lactose. Finally, transcription and translation in vitro of the cDNA corresponding to epsilon BP yielded a polypeptide containing carbohydrate-binding activity. All of these results strongly support the conclusion that CBP35 and epsilon BP are mouse and rat homologues, respectively.
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M3 - Article
C2 - 2536691
AN - SCOPUS:0024961719
VL - 264
SP - 1097
EP - 1010
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 4
ER -